I am convinced of the potential of design to make a huge difference to our hidden ecological impacts, but I also recognise that sustainable design often complements changes in behaviour and lifestyle. This isn't an either/or but a subtle interplay in which design and behaviour work together to create new worlds.
I've been contemplating these new worlds at a humble level in the specification of the small laundry for Tree House, which will soon fill out from its newly laid screed floor.
Is it enough to buy the most efficient washing machine and tumble dryer and carry on as usual? Well, no. Thoroughgoing eco-design requires that we consider the whole process, rather than just tweaking the details.
Laundries have been banished from modern homes by the ascendancy of white goods, often turning washing into a mechanistic chore, rather than a task undertaken with thought and care. The design decision to include a dedicated laundry space in Tree House is therefore a deliberate attempt to improve both our technology and our actions.
On one side of the room will sit our washing machine; on the other, a large reclaimed butler sink. How many of the items in our laundry basket will really require a machine wash and how many will be happy with a quick cool stir? After all, we're a couple of urban professionals (albeit male ones), not coal miners.
Although we may not always choose to use it, our AEG-Electrolux washing machine is an eco-design success story (www.aeg-electrolux.co.uk). It requires only 39 litres of water per wash, a third of the consumption of a 10-year-old machine, and only one kilowatt-hour of electricity.
It is also designed to optimise our behaviour by incorporating a weight sensor which indicates when a full load is reached. This is important because most people consistently underload their washing machines and so end up using them more often than they need to.
Then we face the tricky issue of drying. Here there is no eco-design quick fix: even an A-rated tumble dryer will gobble lots of energy to perform a task that takes place naturally for free. Gas-fired dryers have much lower carbon emissions than the familiar electric models, but they still can't match the environmental credentials of the humble washing line.
Our small back garden will have a retractable washing line, but even this simple technology fails in the winter. So, above our washing machine we will be installing a brilliant piece of Victorian eco-design, the clothes-airer. This simple contraption is lowered to hang damp clothes then raised on pulleys to make the best use of the warm air collecting at ceiling height.
As few high street shops sell them, I purchased our Victorian original through eBay just before it got thrown into a skip. You can, however, buy a contemporary clothes airer and plenty of accompanying eco-friendly detergents from the Natural Collection (www.naturalcollection.com, 0870 331 33 33).
Hopefully, the laundry at Tree House will turn good design into good behaviour: within a few weeks, Ford and I expect to be the best-behaved laundry boys in south London.
Will Anderson's complete 'Diary Of An Eco-Builder' will be published by Green Books in spring 2006.